Curtain wall construction



y 0, 1967 R. A. FERRELL. ETAL 3,321,880

CURTAIN WALL CONSTRUCTION 2 Sheets-Sheet 1:

Filed Sept. 14, 1964 INVENTORS RUSSELL A. FERRELL NORBERT HOWE y 30, 1957 R. A. FERRELL ETAL 3,321,880

CURTAIN WALL CONSTRUCTION Filed Sept. 14, 1964 2 Sheets-Sheet 2 INVENTORS RUSSELL A. FERRELL NORBERT c. HOWELL ATTORNEV United States Patent 3,321,881 CURTAIN WALL CONSTRUCTION Russell A. Ferrell, Richmond, and Norbert C. Howell,

Connersville, Ind., assignors to H. H. Robertson Company, Pittsburgh, Pa, a corporation of Pennsylvania Filed Sept. 14, 1964, Ser. No. 396,221) 3 Claims. (#81. 52-235) The present invention concerns curtain wall construction, and more particularly, a curtain wall construction which utilizes the stick principle wherein a plurality of vertical mullions are initially secured to a building frame work.

The present curtain wall can terior of the building, thereby eliminating the need for exterior scaffolding. The present curtain wall assembly is free of visible fasteners, both internal and external, which is an aesthetic advantage and also minimizes dismantling of the wall through vandalism. The present curtain wall assembly provides the outer surfaces of glazing and of infill panels in the same vertical outer plane. The present curtain wall assembly permits replacement of broken glazing without requiring disassembly of large areas of the entire wall. The glazing replacement can be performed conveniently from the interior of the building.

The present curtain wall is relatively lightweight yet remarkably strong as a result of external outboard ribs on the vertical mullions which cooperate with a snap-in decorative strip. Provision of the snap-in decorative strip permits the use of diverse color and texture components for the external surface of the vertical mullions in addition to achieving a relatively low cost assembly. The present curtain wall assembly utilizes a relatively small number of different pieces or elements.

This invention will be more fully described in the following detailed description by reference to the accompanying drawings in which:

FIGURE 1 is a fragmentary perspective illustration of the present curtain wall assembly from an interior vantage-point;

FIGURE 2 is a fragmentary perspective illustration of an anchoring means for the vertical mullions of this invention;

FIGURE 3 is a fragmentary perspective illustration of an alternative means for anchoring the vertical mullions of this invention;

FIGURE 4 is a fragmentary perspective illustration, similar to FIGURE 1, showing the present curtain wall in a partially exploded View;

FIGURE 5 is a fragmentary perspective illustration of the present curtain wall assembly after infill panels have been secured and prior to installation of glazing;

FIGURE 6 is a fragmentary perspective view of a length of vertical retainer channel for securing glazing in the present curtain Wall assembly;

FIGURE 7 is a fragmentary perspective view of the present curtain wall assembly from an exterior vantage point showing the snap-in decorative strip; and

FIGURE 8 is a fragmentary perspective view of a length of glazing retainer channel and, in phantom outline, a cross-section of a horizontal muntin.

Referring to FIGURE 1 the present curtain wall is identified generally by the numeral 10. In FIGURE 1, the curtain wall 10 is shown as it is seen from the interior of the building. In general, the present curtain wall 19 includes vertical mullions 11, horizontal muntins 12, generally rectangular infill panels 13, glazing sheets 14, and vertical retainer strips 15, 16.

The vertical mullions 11 are slideably secured to a building framework at at least two points along their be assembled from the inlength in any suitable manner, for example, as shown in FIGURE 2, by means of a structural angle 17 and plate 18. The structural angle 17 normally is secured to the building framework (a girder, column, subgirt, or concrete floor) by means of a bolt extended through an elongated bolt slot 19. The structural plate 183 is fastened to the anchor angle 17 by means of fasteners extending through holes (not seen) in the structural plate 18 and through elongated bolt slots 20. The vertical mullion 11 is secured to the structural plate 18 by means of fasteners passing through elongated bolt slots 21. By virtue of the slideable fastening of the vertical mullions 11', they are free from stresses resulting from thermal expansion and contraction.

As can be seen in FIGURE 2, the vertical mullion 11 has a generally T-shaped cross-section and includes a base portion 22 having a central Web 23 extending inboard from its center, and having a pair of panel engaging flanges 24 extending inboard at each end. In the preferred embodiment, the base portion 22 has a pair of outboard extending ribs 25- which are generally parallel with each other. The ribs 25 have a linear bead 26 vertically disposed along the confronting faces thereof. The central web 23 terminates in an open channel 27 which is adapted to receive a self-threading fastener. The vertical mullion 11 preferably is fabricated as an extruded rail product of aluminum or aluminum alloys.

Normally the vertical mullion 11 of FIGURE 2 will be fastened to the building framework by means of an anchoring device at each floor level, in the well-known manner seen in US. Patent 3,038,568. At the top or bottom of the building wall, the vertical mullion 11 can be secured to a head channel or base channel in a manner as seen in FIGURE 3 where a head channel 28 is illustrated. The head channel 28 has a base 29, an internal leg 30 and an external leg 31. The head channel normally will be secured to the building framework under an cave and customarily will be sealed by means of a suitable caulking material which is applied to a serrated surface of the base 29. The external leg 31 is provided with a pair of fastener receiving holes 32. At the upper end of the vertical mullion 11, the central Web 23 and the panel engaging flanges 24 are cut away for a distance corresponding to the height of the external leg 31. A pair of elongated bolt slots 33 is provided in the base portion 22 and fasteners are extended through the openings 32, 33 for slideable securing of the vertical mullion 11 at its upper end. The elongated bolt slots 33 allow for stress-free thermal contraction and expansion of the mullions 11.

Wall assembly After the required vertical mullions 11 'have been secured to the building framework, the desired infill panels are installed. The infill panels 13 are shown in FIGURE 4 as including an exterior surface plate 41 and an interior surface plate 41. Such infill panels are well known in the curtain wall art and are shown, for example, in US. Patents 2,949,981 and 3,110,370. Thermal insulating material 42 (glass fiber batts, mineral wool, foamed plastics, et \cetera) customarily is provided between the external sheet 41 and the interior surface plate 41. The interior surface plate 41 comprises the base member of a unitary box-like structure which includes flanges on top, bottom and sides which are folded from the same sheet which comprises the interior surface plate 41. It will be observed that the infill panel has a horizontal metal surface 43 at the top which is one of the flanges just described.

A horizontal muntin 12 is secured to the infill panel 13 by means of threaded fasteners 44 which extend through the inboard central web 45 of the horizontal muntin 12. Thus each panel 13 with its top muntin and its bottom muntin comprises a unitary structure.

The horizontal muntin 12 seen in FIGURE 4 has a generally T-shape cross-section and includes a generally vertical base element 46 with panel engaging inboard flanges 47 at each end and with an inboard central horizontal web 45.

As can be seen in FIGURE 4, the vertical mullion 11 has been slotted by removal of the panel engaging flanges 24 as seen at A. The cutaway portion of the panel engaging flanges 24 corresponds to the height of the vertical base element 46 of the horizontal muntin 12. Accordingly the infill panel 13 with a horizontal muntin 12 attached to top and bottom can be fitted snugly between a pair of adjoining vertical mullions 11. The panel engaging flanges 24 abut the exterior surface plate 411 of the panel 13 whereas the outer surface of the base element 46 rests within the slot at A in abutment with the inboard surface of the base portion 22.

After panels 13a, 1311 have been secured between adjacent vertical rnullions 11, a vertical panel retaining strip 15 is applied to the vertical mullion 11 by means of a threaded fastener 48 which is threadcdly engaged in the fastener receiving channel 27. The resulting assembly is seen in FIGURE 5. The vertical panel retaining channel 15 has a pair of panel engaging flanges 49 (best seen in FIGURE 4) at each edge and a pair of lateral grooves 50 adapted to receive a snap-on interior cover strip 51 which is shown in FIGURE 4 and will be hereinafter described.

It can be seen from FIGURE that the vertical panel retainer terminates at about the level of the horizontal muntins 12. After all of the panels 13a, 13b have been installed, it will "be seen that the inboard panel engaging flanges 24 (of the mullion 11) are coplanar with the panel engaging flanges 47 (of the mullion 11). Rectangular sheets of glass 14 are introduced above the horizontal muntin 12 and between adjacent vertical mullions 11 and are held in place along their vertical edges by means of glazing retainers 16 as seen in FIGURE 1. The glazing retainer 16 itself is more fully illustrated in FIGURE 6 as including a base portion 52, outboard flanges 53 and re-entrant sloped lips 54. Along the edges of the Web 52 are lateral grooves 55 corresponding with the lateral grooves (of the vertical panel retainer 15) for receiving a snap-on interior cover strip 51 as will be hereinafter described. A continuous bead of caulking material 56 (FIGURE 1) is disposed between each pair of the inboard panel engaging flanges 24. A further bead of caulking material 57 (FIGURE 5) is disposed along the interior surface of the base element 46 of the horizontal muntin 12. A tapered resilient glazing head 58 (formed from plastic, rubber, et cetera) is positioned between glass 14 and the sloping lips 54 of the vertical glazing retainer 16. Threaded fasteners 59 pass through the base portion 52 of the vertical glazing retainer 16 into the {fastener receiving channel 27 of the vertical mullion 11. As the fasteners 59 are tightened, the sloping lips 54 compress the tapered resilient glazing bead 58 against the glazing 14 and in turn compress the caulking bead 56.

Both of the vertical retainers 15, 16 are essentially channel-shaped with the glazing retainer 16 having a greater width than the panel retainer 15 to accommodate the fact that the glazing 14 is thinner than the infill panels 13. Yet the grooves 51), of the retainers are essentially colinear for receiving an interior cover strip 51.

The top edge and bottom edge of the glazing 14 are secured by means of a snap-in glazing channel 66 as seen in FIGURE '8.

The snap-in glazing channel 60 has a hook-shaped front lip 61 which engages a grooved head 62 (of the horizontal muntin 12) and a hook-shaped rear lip 63 which engages a grooved bead 64 (at the inboard end of the horizontal muntin 12). The snap-in glazing channel 60 has a sloped forward surface 65 for engagement with a tapered resilient glazing bead 66 as seen in FIGURE 1. It will be observed that the glazing channel 60 is flush at its inboard end with the inboard end of the horizontal muntin 12, and serves to cover the fasteners 47, serves to retain the glazing 14 along its top edge and bottom edge, and is itself free of exposed fasteners.

After the infill panels 13 and glazing 14 have been secured in the manner shown in FIGURE 1, a snap-on vertical cover strip 51 is applied to the vertical retainers 15, 16. The snap-on cover strip 51 is channel-shaped with a pair of inwardly extended beads 67 as seen in FIGURE 4. The beads 67 engage the lateral grooves 50 (of the panel retainer 15) and the lateral grooves 55 (of the glazing retainer 16). After the vertical cover strip 51 has been applied, the fasteners 48, 59 are hidden from view and protected from access.

One or more weep holes 68 is drilled through the base element 46 of the muntin 12 to allow for discharge of condensed moisture from the building interior, as seen in FIGURE 5.

Exterior appearance The exterior appearance of the present curtain wall is seen in FIGURE 7. It will be observed that the glazing 14 and the exterior surface sheet 40 of the infill panels 13 lie in the same vertical plane and are sealed peripherally against entry of moisture into the building. The base element 46 of the horizontal muntins 12 extends outboard from the exposed surfaces of the glazing 14 and the exterior surface plate 40 of the infill panels 13.

The decorative snap-in strip 70 is installed between the outboard ribs 25 of the vertical mullion 11, generally parallel with the base portion 22. The snap-in strip 70 is retained by suitable linear retaining means extending along the confronting faces of the outboard ribs 25, such as the opposed beads 26. The decorative snap-in strip 70 has along its side surfaces grooves 71 which are engageable with the opposed beads 26 of the outboard ribs 25. The decorative snap-in strip 70 preferably is fabricated from aluminum or aluminum alloys and may be anodized, coated with porcelain enamel, painted, covered with suitable plastic films, or in a similar manner he provided with a distinctive appearance and, if desired, a distinctive texture, to be readily distinguished from the metallic appearance of the extruded vertical mullions 11. Of course it is possible that the decorative snap-in strip 70 be fabricated from and have the same appearance as the material which is used to fabricate the mullions 11. Availability of a wide variety of surface finishes for the decorative snap-in strip 70 permits great variety in the aesthetic color combinations which can be selected by an architect in his building design.

However, the decorative snap-in strip 70 has an important functional purpose. By spanning the distance between the parallel outboard ribs 25, a box-like, rigid mullion results from the base portion 22, the two outboard ribs 25 and the snap-in strip 70. The snap-in strip 70 thus supports the outboard ribs 25 against buckling and allows them to resist the exterior bending stresses which are experienced in bulidings. Extruded box-like mullions are known (US. Patent 3,009,548) but are relatively costly extruded shapes in contrast to unenclosed extruded shapes. By means of the present decorative snap-in strip 76, the strength benefits of a box-like mullion are achieved without requiring the expensive extrusion of an enclosed structure. Thus a strong wall grid Work is provided in the present curtain wall with a relatively lightweight assembly.

As a still further alternative embodiment, the decorative snap-in strip 70 may be fabricated from a lighttransmissive substance (transparent or translucent) such as glass or plastics. Suitable sources of illumination may be positioned within the box-like mullion 11 between the outboard extending ribs 25 and behind the decorative snap-in strip 70 whereby the vertical mullion will present an attractive glowing appearance through such lighttransmissive decorative snap-in strip 7 t We claim:

1. In a curtain wall having a plurality of vertical mullions secured to a building framework and a plurality of generally rectangular infill panels secured between thereof, whereby the said vertical flanges are disadjacent ones of the said vertical mullion, the improveposed outboard from the outer face of the said infill ment comprising in combination: panel;

each said vertical mullion comprising in cross-section opposed grooves in the said panel-abutting flanges of (a) a base portion, (b) an inboard central web eX 5 tended from the center of the said base portion, and (c) panel-abutting flanges extended inboard from the said base portion along the edges thereof, said central web being secured to said building framework at at least two points along the length of the said vertical mullion;

the said vertical mullion which receive the end portions of the said horizontal muntins inboard of the said base portion thereof whereby the said infill panels and horizontal muntins are retained between adjacent vertical mullions;

U-shaped panel-detaining channels having a base which is detachably secured to the said central web of the a pair of horizontally muntins each having a generally -shaped cross-section including a horizontal web and a pair of vertical flanges, said muntins corresponding in length with the width of the said infill panels and being secured one to the top and one to the bottom of the said infill panel by separate fastensaid vertical mullion and having outboard flanges which abut the inboard surfaces of the said infill panels.

3. In a curtain wall having a plurality of vertical mullions secured to a buliding framework and a plurality of generally rectangular infill panels and rectanguing means, whe eby the aid v rti al flanges a lar glazing sheets being secured between adjacent ones disposed outboard from the outer face of the id of the said vertical mullions, said panels being thicker infill panel and each said panel with its top muntin 2 than the said glazing sheets, the improvement comprising: and bottom muntin comprises a unitary structure; each said vertical mullion having a T-shaped crossopposed grooves in the said panel-abutting flanges of section with a base portion and an inboard central the said vertical mullion which receive the end e t e Outer Surfaces of Said infill. panels and portions of the said horizontal muntins inboard of S g ng being e senti lly coplanar and in abutthe said base portion thereof whereby the said infill 5 ment with the said base portion of the said mullion; panels and horizontal muntins ar retained betw two channel-shaped vertical retainers each being secured adjacent vertical mullions; to the said central web, and one being a glazing re- U-shaped panel-retaining channels having a base which taiIleI having a greater Width than the other n vis detachably secured to the said central web of the ing its legs abutting the inner surface of the said glazsaid vertical mullion and having outboard flanges 1115, and the other being a Panel retainer and having which abut the inboard surfaces of the said infill its legs abutting the inner surface of the said infill panels. panels; 2. In a curtain Wall having a plurality of vertical the two said vertical retainers having a colinear remullions secured to a building framework and a pluoel lng means;

a channel-shaped vertical cover element being secured along its legs by the said colinear receiving means of both said vertical retainers.

rality of generally rectangular infill panels secured between adjacent ones of the said vertical mullions, the improvement comprising in combination:

each said vertical mullion comprising in cross-section (a) a base-portion, (b) an inboard central web extended from the center of the said base portion, and 40 (c) panel-abutting flanges extended inboard from References Cited UNITED STATES PATENTS the said base portion along the edges thereof, said 21 2 central web being secured to said building frame- V 3147518 9/1964 Horgan X work at at least two points along the length of the 3:168:17) 2/1965 Thom X salftvertlcalmunmm 3,176,806 4/1965 Ferrell 52-495 X a pair of horizontal muntlns each having a generally 3 221 453 12/1965 Lietarert X T-shaped cross-section including a horizontal web 3223209 12/1965 Skmmeda X and a pair of vertical flanges, said muntins corre- 3226907 1/1966 Gregoire 52 28 X sponding in length with the width of the said infill panels and being secured one to the top and one to FRANK L. ABBOTT Primary Examiner. the bottom of the said infill panel by means of fasteners extended through the said horizontal webs JOHN MURTAGH, Examiner- 

1. IN A CURTAIN WALL HAVING A PLURALITY OF VERTICAL MULLIONS SECURED TO BUILDING FRAMEWORK AND A PLURALITY OF GENERALLY RECTANGULAR INFILL PANELS SECURED BETWEEN ADJACENT ONES OF THE SAID VERTICAL MULLION, THE IMPROVEMENT COMPRISING IN COMBINATION: EACH SAID VERTICAL MULLION COMPRISING IN CROSS-SECTION (A) A BASE PORTION, (B) AN INBOARD CENTRAL WEB EXTENDED FROM THE CENTRE OF THE SAID BASE PORTION, AND (C) PANEL-ABUTTING FLANGES EXTENDED IN BOARD FROM THE SAID BASE PORTION ALONG THE EDGES THEREOF, SAID CENTRAL WEB BEING SECURED TO SAID BUILDING FRAMEWORK AT AT LEAST TWO POINTS ALONG THE LENGHT OF THE SAID VERTICAL MULLION; A PAIR OF HORIZONTALLY MUNTINS EACH HAVING A GENERALLY T-SHAPED CROSS-SECTION INCLUDING A HORIZONTAL WEB AND A PAIR OF VERTICAL FLANGES, SAID MUNTINS CORRESPONDING IN LENGHT WITH THE WIDTH OF THE SAID INFILL PANELS AND BEING SECURED ONE TO THE TOP AND ONE TO THE BOTTOM OF THE SAID INFILL PANEL BY SEPARATE FASTENING MEANS, WHEREBY THE SAID VERTICAL FLANGES ARE DISPOSED OUTBOARD FROM THE OUTER FACE OF THE SAID INFILL PANEL AND EACH SAID PANEL-ABUTTING FLANGES OF AND BOTTOM MUNTIN COMPRISES A UNITARY STRUCTURE; OPPOSED GROOVES IN THE SAID PANEL-ABUTTING FLANGES OF THE SAID VERTICAL MULLION WHICH RECEIVE THE END PORTIONS OF THE SAID HORIZONTAL MUNTINS INBOARD OF THE SAID BASE PORTION THEREOF WHEREBY THE SAID INFILL PANELS AND HORIZONTAL MUNTINS ARE RETSINED BETWEEN ADJACENT VERTICAL MULLIONS; U-SHAPED PANEL-RETAINING CHANNELS HAVING A BASE WHICH IS DETACHABLY SECURED TO THE SAID CENTRAL WEB OF THE SAID VERTICAL MILION AND HAVING OUTBOARD FLANGES WHICH ABUT THE INBOARD SURFACES OF THE SAID INFILL PANELS. 